Multielectrode lead with multiplexed control and associated connection method

ABSTRACT

The disclosure relates to a lead including a connector for connection to a generator, a demultiplexing circuit receiving at its input on the first conductors of the electrical control signals from the control bus and whose output is connected to a plurality of second conductors contained in the lead and connected to the lead electrodes. The lead further includes a gate and connection circuit component having a body forming a support for an integrated circuit for demultiplexing and defining a set of connection cavities with the second conductor distributed at the periphery of the body around a general axis of the body, and a plurality of connecting elements embedded in the body material, and emerging at an element region and supporting the circuit at respective cavities. The gate and connection circuit component is advantageously made of ceramic-metal.

CROSS-REFERENCE TO RELATED PATENT APPLICATIONS

This application claims the benefit of and priority to French PatentApplication No. 1552894, filed Apr. 3, 2015, which is incorporatedherein by reference in its entirety.

BACKGROUND

The disclosure relates to “active implantable medical devices” asdefined by the Directive 90/385/EEC of 20 Jun. 1990 by the Council ofthe European Communities, specifically the “multisite” implants tocollect electrical potentials and/or selectively deliver electricalpulses to one or more pacing sites of to a set of sites, particularly incardiology and neuromodulation applications.

The recent development of such multi-site stimulation devices has led toincreasing the number of electrodes, so as to allow the choice of one ormore detection/stimulation sites optimizing the operation of the device.

The following disclosure will mainly refer to electrodes used for theapplication of stimulation pulses, but this feature is not limiting andthe disclosure applies equally to the case of electrodes used fordetection of electric potentials collected at specific sites, the sameelectrode possibly being used for both sensing and pacing.

In the particular case of the implantable cardiac devices forventricular resynchronization or “CRT” (Cardiac ResynchronizationTherapy), which are cited here as a non limiting example, a device withelectrodes for stimulating one and the other ventricles is implanted inthe patient. The stimulation of the right ventricle (and right atrium)is done by a conventional endocardial lead, but for the left ventricle,the access being more complex, the stimulation is generally carried outby a lead inserted into the coronary sinus and then pushed into acoronary vein on the epicardium so that the end of the is positioned infront of the left ventricle.

This procedure is, however, rather difficult, because the diameter ofthe coronary vessels is reduced with the progress of the lead, so it isnot always easy to find the optimum position during implantation. Theproximity of the phrenic nerve can also lead to inappropriate stimuli.

To overcome these difficulties, “multielectrode” leads have developed,provided for example with eight or more electrodes, and it is possibleto choose, after implantation, the electrode which corresponds to thesite on which the stimulation is the most effective. This selection ofthe electrode can be carried out automatically by a measure ofendocardial acceleration peaks (PEA), by a measurement of bioimpedance,or from any other sensor able to provide information representative ofthe patient's hemodynamic status. It can also be operated manually bythe practitioner by a suitable programmer controlling a generator.

These pacing leads must have a diameter as small as possible in order toextend the possibilities of implantation while being the least traumaticfor the body.

Furthermore, increasing the number of electrodes creates issues ofdelicate connection at the connection with the stimulation pulsegenerator.

The difficulties encountered are similar in neuromodulation applicationsoperating by multipoint stimulation of the central nervous system.Neuromodulation consists, for example, in implanting a microlead in thecerebral venous network in order to achieve very specific target areasof the brain in order to apply electrical stimulation pulses to treatcertain conditions such as Parkinson's disease, epilepsy, etc. Thepurpose can also be to stimulate the peripheral nervous system, theelectrodes then being placed at nerves or muscles.

With currently known techniques, increasing the number of electrodes tobe connected has a strong impact on the size and cost of internalelectronics of the housing, the connector of the housing and the lead,so it may be preferred to use a demultiplexer circuit which makes itpossible to decode signals and voltages on a limited number ofconductors (typically 2 or 4). It would however be beneficial to be ableto increase the number of electrodes while generally reducing the volumeof connection between the signal source and the lead, requiring onlythat these two or four conductors to power and control thedemultiplexer.

This technique of multiplexing/demultiplexing is already implemented incardiology and neuromodulation applications.

In some cases, the demultiplexing circuit is located in the distalportion of the device, near the electrodes, being incorporated in thelead body. EP 1938861 A1, EP 2465425 A1 and US 2011/301665 A1 describesuch arrangements. But it is noted that in these known constructions,the transverse dimensions of the lead body in its distal part are largerdue to the need to tightly integrate the demultiplexing electroniccircuit.

Alternatively, to avoid this difficulty, an intermediate component ofquite large dimensions is provided midway between the generator and thelead tip (see in particular EP 2727623 A1), which complicates theimplantation and creates a new risk because of the need to implement anadditional element.

Moreover, the evolution of the conductor structures and of the leadelectrode technology is such that it now becomes possible to produceleads with very small dimensions for stimulating and sensing electricalevents in the heart.

Such structures may use conductors of a diameter of 40 to 60 μm and thusmay include a plurality of conductors insulated from each other,typically, up to 100 separate conductors in a diameter less than 0.5 mm.It is not known to associate such structures to multiplexers withoutimmediately meeting the above problems, in particular in terms of size,complexity and cost.

WO 2012/087370 A1 (corresponding to U.S. Pat. No. 8,639,341 B2)discloses an arrangement wherein the demultiplexing circuit isaccommodated in a region of the connector body, with a support andconnection block interposed between the multiplexed conductors and thenon-multiplexed conductors. This block includes, in its center, anelongate support receiving the demultiplexing integrated circuit, wherethe circuit is electrically connected to the two respective groups ofconductors coming from either side of the support. If this arrangementallows incorporating the demultiplexing methods to the connector, it hasthe disadvantage of a large footprint that significantly increases thelength of the connector.

The present invention aims to overcome these limitations of the priorart and to propose a connection solution between a demultiplexer circuitand a multielectrode lead that is reliable and protected while beingcompact and which can be housed in the vicinity the lead connector, notrequiring increase in diameter of the latter, and simplify the structureof the connections of the associated housing.

SUMMARY

The disclosure proposes for this purpose, in a first embodiment, amultielectrode lead including:

A connector for a control and/or power and/or data transfer connection;

A demultiplexing integrated circuit adapted to receive input on firstconductors of the electrical control and/or power and/or data transfersignals from the control and/or power and/or data transfer link andconnected at the output to a plurality of second conductors contained inthe lead;

A gate circuit and connection element having a body forming a supportfor the demultiplexing integrated circuit and housed in a connector bodybearing the connector and

A set of electrodes extending along the lead and connected to the secondconductors.

In some embodiments, the gate circuit and connection element:

Has a generally cylindrical form and receives the integrated circuit onone of its end sides;

Axially extending grooves;

Defines a set of connection cavities having the form of axiallyextending grooves in the periphery of the element body, with at leastthe second conductors distributed around a main axis of the body anddisposed in the connection cavities; and

Includes a set of connection elements embedded in the material of thebody, emerging at a region of the element supporting the integratedcircuit and at the respective cavities, these connection elementselectrically connecting said first and/or second conductors torespective terminals of the integrated circuit.

According to various embodiments:

The conductor elements each have a protruding part extending in arespective groove on at least part of its axial length;

The conductive elements each have a first embedded portion generallyextending axially and whose one end opens at a surface adjacent to theintegrated circuit;

Each conductor element includes an intermediate embedded portiongenerally extending radially between the first embedded portion and theprotruding portion extending in the groove;

The integrated circuit is protected by a cover tightly fixed on the bodyof the gate and connection circuit element;

The gate and connection circuit element is achieved by a ceramic-metaltechnology, the body of the element being constituted by a ceramicregion and the connection elements being constituted by metal regions;

The gate and connection circuit element further includes a metal regionfor the cover welding;

The metal region is an annular region surrounding the integratedcircuit;

The cover is also made of ceramic-metal technology and includes acounterpart metal region of the metal area surrounding the integratedcircuit;

The conductors are surrounded at their free end, received in itsrespective cavity, by a metallic sleeve;

The lead further includes a transition element adapted to retain thesecond conductor in a configuration corresponding to the arrangement ofthe cavities for said second conductors;

The lead further includes a transition element adapted to retain theconductors in a first configuration corresponding to the arrangement ofthe cavities for said first conductors; and

The body of the gate and connection circuit element includes at leasttwo generally coaxial cylindrical portions of different diameters, eachregion having a plurality of axially extending grooves in its periphery.

In some embodiments, the disclosure provides a method for connection ofconductors to a demultiplexing circuit in a localized stimulationmultielectrode lead of the type described above, the method includingthe steps of:

a) mounting the integrated demultiplexing circuit on one of the endsides of the element;

b) connecting the circuit terminals to the emerging parts of theconnection parts in the vicinity of the circuit; and

c) connecting the conductors to the emerging parts of the connectionregions at the cavities.

According to various other embodiments:

Step b) is implemented using connection wires;

Steps a) and b) are implemented simultaneously by a returned chipmounting technique;

Step c) is carried out by laser shots;

The conductors are surrounded at their free end, received in itsrespective cavity, by a metal sleeve;

The metallic material of the sleeve is the same as the metallic materialof the gate and connection circuit element; and

The method further includes steps of:

d) providing a cover at least partially made of metal to protect theintegrated circuit;

e) providing the gate and connection circuit element a metal regionsurrounding the integrated circuit; and

f) fixing the cover to said element by laser shots at the metallicregion.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, characteristics and advantages of the presentdisclosure will become apparent to a person of ordinary skill in the artfrom the following detailed description of preferred embodiments of thepresent disclosure, made with reference to the drawings annexed, inwhich like reference characters refer to like elements and in which:

FIG. 1 and FIG. 1A are overall views in side elevation of amultielectrode lead with multiplexed control according to an embodimentof the disclosure.

FIG. 2 is a perspective view of a gate and connection circuit componentof the lead of FIG. 1.

FIG. 3 is a perspective view of the component receiving a plurality ofconductors for the electrodes and a protection cover of the circuitmounted on the component.

FIG. 4 is a side elevation view of the component of FIG. 2.

FIG. 5 is a front elevation view of the component of FIGS. 2 and 4.

FIG. 6 is an axial sectional view of a component having a differentgeometry from that of FIGS. 2 to 5, equipped with the circuit, thecover, the conductors and a protection jacket.

FIG. 7 is a front view of the representation of FIG. 6.

FIGS. 8 and 9 illustrate the assembly of FIGS. 6 and 7 of the componentwith its cover.

FIG. 10 shows in perspective view a layout of a conductor to beconnected to the component.

FIG. 11 is a partial cross sectional view on an enlarged scale of theconnection region between such a conductor and the component.

FIG. 12 is an exploded perspective view of a component with its cover,of conductors and transition parts for the conductors.

FIG. 13 is a perspective view of a variant of one of the two transitionparts.

FIG. 14 is an axial sectional view of a variant embodiment of thecomponent according to the disclosure equipped with the circuit, thecover and the conductors.

FIG. 15 is a back view of the equipped component of FIG. 14.

FIG. 16 schematically illustrates the successive steps of mounting amultielectrode lead carried out according to the teachings of thedisclosure.

DETAILED DESCRIPTION

Referring firstly to FIGS. 1 and 1A, an integrated demultiplexingmultielectrode lead is shown. The lead includes a tapered intermediatebody 100 housing a gate and connection circuit component 120 as isdescribed below, and a connector 110 with a control and/or supply and/ordata transfer connection 200, typically with two or four conductors. Thelead 300 houses a plurality of conductors 302, typically from eightpairs of conductors to several tens of pairs of conductors, theseconductors being connected to a set of stimulation electrodes 306 spacedalong the lead.

In the example illustrated in FIGS. 1 and 1A the link 200 with 2 (or 4)conductors is a connection incorporated to the connector 110, andconnected to the 2 (or 4) poles 200 a, 200 b of the connector. This is aparticularly advantageous embodiment, since it is able to include themultiplexer stage within the connector, thus without additionalcongestion, in particular in the diametric dimension.

However, it must be kept in mind that the disclosure can be applied tomany other configurations; each time it is necessary to interface adevice with a detection/stimulation multielectrode lead by amultiplexer/demultiplexer stage. The device in question may inparticular be any type of neurostimulator, or pacemaker, and inparticular be in a stand-alone device with its own power supply(leadless implantable capsule) and extended by a multielectrode leadwhich it is connected by a communication system, etc.

Advantageously, but not limiting, the connector 110 is in theillustrated example a standard connector of the IS-1 type (to which twoconductors 202 accommodated in the body 100 are connected, according tothe shown example) or of the IS-4 type (four conductors). The lead 300has in the present example ten conductors 302.

Referring now to FIGS. 2 to 5, a component 120 housed within the body100 is illustrated, whose main functions are to receive an electronicdemultiplexing circuit responsive to the signals coming through theconductors 202, connected to the link 200 by the connector 110, forselectively applying stimulating pulses to one of the electrodes 306 (orto a given subset of said electrodes).

This component includes a generally cylindrical main body defined by acylindrical outer wall 122 in which a series of longitudinal grooves 124are formed, intended, as discussed in the following, to make aconnection with the conductors of the link 200 and the conductors of thelead part 300. In this embodiment, the grooves 124 are twelve in number:two for the conductors 202, departing in the direction of the link 200,and ten for conductors 302, departing towards the lead part 300.

On one of its end faces, here on its proximal face, the component 120receives an integrated circuit 130 for providing the function ofdemultiplexing the signals received via the connection 200 forcontrolling the pulses as described above.

This integrated circuit includes at its surface (or, alternatively (notshown), at its sides), conductive pads or areas 132 allowing theintegrated circuit to be connected to its environment by connectionwires (bonding wires) 140. In the component body a plurality ofconductive elements 126 a-126 c intended to ensure the connectionbetween the circuit 130 and the conductors of the connecting part 200and the lead 300 are embedded, as will be described in detail later.

FIG. 3 illustrates a cover 150 to be fixed tightly on the face of thecomponent 120 receiving the circuit 130, as will be describedhereinafter, so as to protect the circuit 130 and the bonding wires.

Referring to FIGS. 6 to 9 which illustrate a component having a slightlydifferent geometry from that of FIGS. 2 to 5 (mostly with a shorteraxial length), the configuration of the inner conductor elements 126a-126 c of the component 120 can be seen.

Each element includes a first part 126 a extending axially flush at itsfree end on the side of the component body 120 which carries the circuit130, by opening the periphery of the circuit. This first part isextended by a portion 126 b oriented generally radially, towards one ofthe longitudinal grooves 124, each for receiving a conductor 202 or 303.This portion 126 b terminates in a portion 126 c which opens into thegroove 124 extending over at least part of its axial extent.

The electrical connection between the multiplexing circuit 130 and eachof the conductors is carried out, circuit 130 side, by the bonding wire140 welded on the one hand on the conductive pads 132 of the circuit andthe other hand on the flush regions of the portions 126 a of theembedded conductive elements, respectively. The connection ofconductors' side 202, 302 is carried out as will be seen in detail belowby contacting exposed portions of the conductors with the portions 126 cof the conductive elements which open into the respective grooves 124.

According to an alternative embodiment not illustrated, the electricalconnection between the conductive pads of the circuit 130 and therespective conductive elements 126 may be performed according to knowntechnology called “flip-chip”, the chip having slightly protrudingcontacts on its face turned towards the component 120 and these contactsbeing connected to flush areas of the portions 126 a of conductiveelements 126 a-126 c. This technique avoids the use of bonding wires.

Advantageously, the component body 120 and its conductive members 126a-126 c are made of “cermet”, that is to say, a composite material withmetal matrix including a ceramic reinforcement, for example ofalumina/platinum, the main, insulating, part of the body being made ofceramic (here alumina) and the conductive elements 126 being made ofplatinum. Alternatively, one may use a composite of typealumina/tungsten-molybdenum. One can also use a ceramic of the typesilicon carbide.

The manufacturing methods of such elements, which are the advantage of acontinuous transition between the insulating part and the conductivepart are largely controlled and make it possible to manufacture acomponent with a design adapted to this application (sizing of thevarious parts of the device will be discussed below).

Furthermore, the component 120 produced in this way allows, incooperation with a cover 150 as will be described in detail below, tohermetic seal the cavity housing the integrated circuit 130, which maybe difficult to obtain by molding a synthetic material injected on themetallic conductors.

Referring to FIGS. 8 and 9, the cover 150 of the protection circuit 130is incorporated and fixed tightly on the face of the component 120 whichcarries the integrated circuit 130, as illustrated.

The cover is also realized here in cermet technology and includes aninsulating main body forming a cavity 154 intended to house the circuit130 and a conductive annular region 152 facing the component 120. Inassociation with this cover, on component 120 a further conductive area128 of generally annular shape, by example same geometry as the annulararea 152 of the cover, flush with the surface that carries the circuit130, is arranged around the latter. Note that the cermet technology formanufacturing of the component 120 makes it easy to integrate such anannular conductive region.

With such a configuration, once the bonding wires 140 are connected, thecover 150 is applied and maintained against the face of the component120 on the circuit 130 and a welding point by point laser shots is thenimplemented in a plurality of places at the junction between the annularzones 128, 152, the weld points being designated in FIG. 9 by reference170. This method ensures a completely sealed connection between thecomponent 120 and the cover 150, to thereby perfectly protect thecircuit 130 and its connections.

Note here that the principle of closure of the cavity housing thecircuit 130 makes it possible to minimize excessive elevation of thetemperature within the cavity, which can be maintained below 400° C.

It will also be noted here that the configuration of FIGS. 2 and 3 isslightly different from that of FIGS. 5 to 9. In FIGS. 2 and 4, theconductive area for the sealed welding of the cover 150 is designated byreference 129. It extends not in a general radial plane but according toa circumferential cylinder at an area of reduced diameter adjacent toits face supporting the circuit 130, of component 120.

Finally, according to an embodiment, the welded cover 150 may be madeentirely of biocompatible metal, such as titanium alloy.

According to another embodiment, the cover can be fixed tightly on thecomponent 120 by bonding.

In all cases, it may be advantageous to further strengthen theprotection of the circuit and of its associated connections byencapsulating the assembly formed by the component 120 and its cover150, housing the circuit 130, and the connected wires, in a block offlexible polymer 160, for example of silicone, this block also enclosinga short length of the conductors 202, 302 to mechanically secure theassembly.

Referring now to FIGS. 10 and 11, it is described in detail a method inwhich the conductors 202, 302 are mechanically held and electricallyconnected to the component 120, at respective grooves 124.Advantageously, and as illustrated in FIG. 10, such a conductor, here aconductor 302 located electrodes side, receives at one end portion 302 astripped of its insulating sheath 302 b, a hypotube 304 to facilitatethe connection method. This hypotube, here made of platinum, may bewelded to conductor 302 by laser shot, or simply threaded thereon duringassembly.

As shown in FIG. 11, the end of the conductor provided with the hypotube304 is positioned and held in line with a groove 124 corresponding to afinal destination. It is noted that the conductive portion 126 c openinginto the groove 124 forms a semi-cylindrical cavity having a diameterclose to the outside diameter of the hypotube 304 such that it isintimately housed there.

Then a laser shot (or several shots, on each side) is performed at thetransition between the hypotube 304 and the conductive portion 126 c, oneach side, to provide mechanical attachment and electrical connection ofthe group consisting of the core 302 a of the conductor and the hypotube304 with the conductive part 126 c of the conductive elements 126 a-126c, which is connected at the opposite end to the integrated circuit 130.

Note here that the hypotube 304 may reduce the risk of poor connectionduring the laser shot. It may be omitted in the case wherein thereliability of the laser firing method is sufficient, in which case theconductive core 302 a of the conductor 302 is directly welded to thepart 126 c of the conductive element 126 a-126 c (and similarly for theconductors 202).

According to a non-illustrated embodiment, the electrical connectionbetween the component 120 and the conductors 202, 302 may be performedwithout use of laser shot welding. More specifically, by placing theconductors 202, 302 into their respective groove 124 and applying aroundthe entire assembly strapping, for example by use of a PEEK ring(polyether-ether-ketone) which crimps the conductors 202, 302 againsttheir respective conductive parts 126 c. A slight taper from theperiphery of the component 122 may be provided to perform this function,the ring being moved to the portion of larger outside diameter of thecomponent, and then bonded.

Referring now to FIG. 12, advantageously, transition parts, respectively400, 500, are associated with the gate and connection circuit component120 to ensure a prepositioning of the conductors 202, 302 to connect thecomponent, respectively.

Thus, the part 400, made of injected synthetic material, has the shapeof a cylinder with an outer diameter close to that of component 120, andhas in diametrically opposite regions two through holes 402 generallyparallel in the axial direction, the distance between these orificesbeing approximately the distance between two diametrically opposedgrooves 124 of the component. The two conductors 202 are threadedthrough two holes and then engaged in their respective groove 124, thepart 400 ensuring prepositioning of both conductors during the solderingor crimping operations.

In the same spirit, a part 500, also of injected synthetic material,here includes ten through holes 502 generally parallel to the axialdirection, in which the ten conductors 302 are threaded before being putin place in their respective groove. This transition part 500 isgenerally cylindrical, here.

It is understood that these transition parts can be particularly useful,especially at the side of the main portion 300 of the lead, when a largenumber of conductors are to be positioned on the component 120.

After soldering or crimping of conductor, parts 400, 500, for examplebonded to both sides of the component 120 with its cover 150, ensuredimensional stability of the assembly and prevent the conductors frombeing accidentally folded and optionally cut during handling.

As shown in FIG. 13, we can give the transition part 500 a generallyconical shape, the orifices 502 converging from an area adjacent to thecomponent 120, where they adopt an arrangement corresponding to that ofcounterpart grooves, in direction of a distal narrowed area where allconductors 302 join in the portion of the lead 300.

We will now describe with reference to FIGS. 14 and 15 an alternativeembodiment of the gate and connection circuit component, allowing theconnection of an increased number of conductors 302.

In this embodiment, the gate and connection circuit component designatedby the reference 120′ comprises three cylindrical stages for peripheralconnections with conductors, coaxial and of progressively decreasingdiameter as the distance increases from the part supporting theintegrated circuit 130.

Thus, FIGS. 14 and 15 illustrate a first set of grooves 124 made in theregion of the widest stage, a second set of grooves 124′ formed throughthe following stage, of intermediate diameter, and a third set ofgrooves 124″ performed at the top stage of smaller diameter.

The component 120 houses three groups of embedded conductive elements,respectively 126, 126′ and 126″, whose configurations are adapted to thegeometry of the component body to provide each a flush connectionsurface, these connecting surfaces being distributed around the circuit.

The cylindrical peripheries of the three stages are designated byreferences 122, 122′ and 122″.

It is understood that such a configuration may significantly increasethe connection density. Typically it becomes possible to connect up to ahundred or more conductors 302, to make leads provided with very manyelectrodes, providing excellent opportunities for stimulation location.

Advantageously, the component 120′ according to this embodiment is alsomanufactured according to the cermet technology, and the transition part500, if such a part is provided, is adapted accordingly.

The disclosure enables a multielectrode lead with microconductors, of atypical diameter of 0.3 mm with current technology, with an intermediateportion dedicated to both the connection to a connector (e.g. a standardconnector of IS-1 or IS-4 type) and to demultiplexing, whose diameterdoes not exceed 3 to 4 mm (with a chip having a size of 1 mm², which canbe achieved with the current integration of performance).

The present disclosure has many advantages, including the following:

It makes possible the integration of the demultiplexing in the lead,while keeping it a small diameter, typically of the order of 0.3 mm inthe current technology, with a gradual transition between the housingfor the demultiplexing circuit and the lead itself;

It is compatible with a standard connector (e.g. type a 2 wire IS-1connector or a 4 wire IS-4 connector) and allows miniaturization of theregion dedicated to the demultiplexing of the signals arriving at theseconnectors;

Manufacture may be economical, with welds by a laser shooting robot oncomponents whose cost can remain reasonable;

It can significantly increase the number of connections (100 connectionsor more) while maintaining a reasonable size for the demultiplexingpart;

It ensures a tightness and protection of the area housing thedemultiplexing integrated circuit through hermetically fixing the coverand optionally the encapsulation in a soft polymer; and

It enables very short electrical connections, with low risk of incorrectconnections due to conductor breaks.

As regards more particularly the manufacturing method of amultielectrode lead formed according to the teachings of the presentdisclosure, it can be summarized schematically to the steps shown in theflowchart 400 of FIG. 16, namely:

Component 120 manufacturing (step 410);

In parallel, preparation of the integrated circuit chip 130 (step 420);

Mounting the chip 130 on the component 120 and realization of connectionbonding 140 (step 430);

Laying and sealing of titanium cover 150 on the component 120 (step440);

Preparation of the lead (step 450), then mounting of the hypotube 304and placement and welding of the conductors 202, 302 on the component(step 460); and

Finally, encapsulation of the assembly with the lead and the varioussubassemblies of the connector 110 (step 470).

What is claimed is:
 1. A multielectrode lead for localized stimulation,comprising: a connector for at least one of electrical control, powersupply, or data transfer connection; an integrated demultiplexingcircuit adapted to input, from a plurality of first conductors, at leastone of electrical control, power supply, or data transfer signals fromthe at least one of electrical control, power supply, or data transferconnection, and connected to a plurality of second conductors containedin the lead; a gate and connection circuit element having a body forminga support for the demultiplexing integrated circuit and housed in aconnector body carrying the connector; and an electrode assemblyextending along the lead and connected to the second conductors, whereinthe gate and connection circuit element: is of a cylindrical form andreceives the integrated circuit; defines a set of connection cavitieshaving a form of axially extending grooves in a periphery of the body ofthe gate and connection circuit element, with at least the secondconductors are distributed around the periphery of the body around ageneral axis of the body and disposed in the connection cavity; andcomprises a plurality of conductive elements embedded in a material ofthe body, emerging at a region of the element supporting the integratedcircuit and at respective cavities, these connection elementselectrically connecting the first and/or second conductors to respectiveterminals of the integrated circuit.
 2. The lead of claim 1, whereineach of the conductive elements have a protruding part extending in arespective groove on at least part of its axial length.
 3. The lead ofclaim 1, wherein the conductive elements each have a first embeddedportion generally axially extending and having one end opening at asurface adjacent to the integrated circuit.
 4. The lead of claim 3,wherein each conductive element comprises an intermediate embeddedportion generally radially extending between the first embedded portionand the protruding part extending in the groove.
 5. The lead of claim 1,wherein the integrated circuit is protected by a cover sealingly fixedto the body of the gate and connection circuit element.
 6. The lead ofclaim 5, wherein the integrated circuit is protected by a coversealingly fixed to the body of the gate and connection circuit element,and wherein the gate and connection circuit element further comprises ametal region for welding the cover.
 7. The lead of claim 6, wherein themetal region is an annular region surrounding the integrated circuit. 8.The lead of claim 6, wherein the cover is made of metal-ceramictechnology and comprises a homologous metal region of the metal regionsurrounding the integrated circuit.
 9. The lead of claim 1, wherein thegate and connection circuit element is formed by a metal-ceramictechnology, the body of the gate and connection circuit elementcomprising a ceramic region and the connection elements comprising aplurality of metal regions.
 10. The lead of claim 9, wherein theconductors are surrounded at a free end received in a respective cavityby a metal sleeve.
 11. The lead of claim 1, further comprising atransition member adapted to retain the second conductors in aconfiguration corresponding to the arrangement of the cavities for thesecond conductors.
 12. The lead of claim 1, further comprising atransition member adapted to retain the first conductors in aconfiguration corresponding to the arrangement of the cavities for thefirst conductors.
 13. The lead of claim 1, wherein the body of the gateand connection circuit element comprises at least two cylindricalregions, generally coaxial and of different diameters, each regionhaving a plurality of grooves axially extending at a periphery.
 14. Animplantable medical device, comprising: a stimulation pulse generator;and a multielectrode lead comprising: a connector for at least one ofelectrical control, power supply, or data transfer connection; anintegrated demultiplexing circuit adapted to input, from a plurality offirst conductors, at least one of electrical control, power supply, ordata transfer signals from the at least one of electrical control, powersupply, or data transfer connection, and connected to a plurality ofsecond conductors contained in the lead; a gate and connection circuitelement having a body forming a support for the demultiplexingintegrated circuit and housed in a connector body carrying theconnector; and an electrode assembly extending along the lead andconnected to the second conductors, wherein the gate and connectioncircuit element: is of a cylindrical form and receives the integratedcircuit; defines a set of connection cavities having a form of axiallyextending grooves in a periphery of the body of the gate and connectioncircuit element, with at least the second conductors are distributedaround the periphery of the body around a general axis of the body anddisposed in the connection cavity; and comprises a plurality ofconductive elements embedded in a material of the body, emerging at aregion of the element supporting the integrated circuit and atrespective cavities, these connection elements electrically connectingthe first and/or second conductors to respective terminals of theintegrated circuit.
 15. The implantable medical device of claim 14,wherein the device is a pacemaker or a neurostimulator.
 16. Theimplantable medical device of claim 14, wherein each of the conductiveelements have a protruding part extending in a respective groove on atleast part of its axial length.
 17. The implantable medical device ofclaim 14, wherein the conductive elements each have a first embeddedportion generally axially extending and having one end opening at asurface adjacent to the integrated circuit.
 18. The implantable medicaldevice of claim 17, wherein each conductive element comprises anintermediate embedded portion generally radially extending between thefirst embedded portion and the protruding part extending in the groove.19. The implantable medical device of claim 14, wherein the integratedcircuit is protected by a cover sealingly fixed to the body of the gateand connection circuit element.
 20. The implantable medical device ofclaim 19, wherein the integrated circuit is protected by a coversealingly fixed to the body of the gate and connection circuit element,and wherein the gate and connection circuit element further comprises ametal region for welding the cover.